Had to reclean the RAVES after 10 hours!!!

[scooper77515]

Wassup?

It started with blowing by the bellows and melting the bellows and caps, so I bought all new rubbers, caps, springs, gaskets, o-rings, and cleaned everything really good. Took it out for 2 days of 3-4 hours running each, get it home and find that one of the valves is only opening halfway, and blowing by the bellows again. Oil all over the top of my engine.

What am I doing wrong?

I am using a fine wire-wheel on the valves to get the carbon and oil off, and get them "SHINEY" and polished before I put them back in. They seem to be fouling as quick as my spark plugs.

Any suggestions?

 

[kustomkarl]

Scott, check the O ring on the guillotine to see if it needs replacement.

Karl

 

[scooper77515]

Everything is new. I took all the old stuff off for spares, and ran the boat on the XP parts for a few weeks while the boat parts came in. The only reused part is one of the guillotines.

No problems with the XP parts.

When one of the caps/bellows/pistons all melted, it stripped the threads at the top of one of the guillotines when I unscrewed the melted plastic, so one of those is new too.

The only difference is the XP valves do not have 2 grooves cut up and down the length of the guillotine. I wonder if gas is seeping up those grooves???

If i keep having problems, I will buy 2 96 XP non-grooved guillotines and see if that fixes it.

Link goes to groovy valves from Challenger...XP is smooth on both sides.

 

[kustomkarl]

It just might be the guillotines are bad...Let me know how you make out. That's the first time I heard of that kind of problem.

Karl

 

[scooper77515]

Taking it out waterskiing in about an hour, and will let you know how things look and act.

It usually takes two trips, but I may pop them out this afternoon just to take a look.

 

[timmyboy76]

L U C K eee...

 

[Squidoo]

What oil are you using?

 

[scooper77515]

Spam! Spam! Spam!!!

Using XP-S semi Synthetic. Karl says that is all he ever used in it, and when I bought the boat, I bought 2 gallons from him.

For those reading my other thread, that same cylinder let loose the day I went waterskiing. Cratered something, and had half a cup of cast aluminum chunks on top of that piston. So WARNING!!! If your RAVES start to do this, take a closer look because your engine may be on it's final runs...

When I get the new motor, I will take this one apart and see what failed, and let everyone know. And rebuild it if there is enough left to rebuild.

 

[kustomkarl]

I believe the oil is XP-S Synthetic blend... not semi Synthetic.

Karl

 

[seadoosnipe]

Rave valves.......

Scott, those are the wrong rave valves for your 787cc engine. Your suppose to be running the flat sided raves. This is going to most likely be your problem.

Look at the bottom of this thread. You'll see my link to the 787. Post 4, 5, 6, and 7 show the RAVE from my 97, 787cc enigne...........check it out.

I've looked at several year model Rotaxs, looking for this type of guillotine and can't find one. Even the 951 has a flat slide.

Get rid of the grooved guillotine and go to the smooth one. I"m going to continue to look for this slide valve to see which model it was made for.:cheers:

 

[scooper77515]

I figured it was those grooves letting hot gasses past. Didn't do it with the flat XP valves.

I wondered if they made them like that to lighten them or something.

I will make sure I have flat valves when I get the new motor.

Karl, you are right, Synthetic BLEND, not SEMI.

 

[robin savell lloyd]

I figured it was those grooves letting hot gasses past. Didn't do it with the flat XP valves.

I wondered if they made them like that to lighten them or something.

I will make sure I have flat valves when I get the new motor.

Karl, you are right, Synthetic BLEND, not SEMI.

I am not sure if the groves I am thinking of are the same as you are talking about but the new inproved rave valves that are not supose to break as easly have the groves in them and I have read that you should replace old rave valves with the new style if you still have the old style in your engine as if the stem breake it can fall and damage the piston. but I can all ways be wrong so do your home work.

 

[vilord]

Do the valves go in only one way? I would think the grooves would go on the manifold side, rather than the engine side...

 

[seadoosnipe]

Yes.........

Yes, RAVES are only meant to go in one way. The edge of the guillotine slide is tapered to fit the piston at the same angle. There is also a mark on them that says "UP".

In all the models I'm looking through in the manual, I have seen NO RAVE valve by Bombardier that has any grooves in them. I know Rotax has a patent on this power valve, but now I"m wondering if there is another PWC corporation that has paid Rotax for the use of their design. It was a "first of it's kind". That' the only possibility I can see. I have looked through shop manuals from 1996, on the first 787 models, through the 2005, 947 engines with RFI, and DI motors...........all of them still look the same. Flat sided and smooth...

Scooper........are there any numbers or markings on that guillotine slide valve?

 

[robin savell lloyd]

In 1997 seadoo came out with a upgraded rave valve it has the # 353 cast into it. These new rave valves have 2 slots in the bottom face of each valve. These valves are stronger and should be installed in every 787 that has the old style # 352 cast valve in them. Hope this helps :cheers:

 

[seadoosnipe]

Thanks Robin.........

Thanks Robin, I will research this. They must not have used them very long. I looked in the 96 manual, but not the 97.

He's obviousy got the same heads as mine, because if they were correct, the the casting would support the grooves and not allow the hot gases into the bellows chamber...............

Thanks again, I WILL be looking into this................:cheers:

 

[vilord]

I saw an ebay auction for a used valve with the grooves in it here.

I asked the guy what they came from, and he said they're from a '98 SPX. So it is verified that at least the '98 has grooves from the factory.

 

[scooper77515]

I finally got most of the stuff back out of the garage following the hurricane, and got to the valves.

They have "358" on them.

 

[gsxkydd]

My front cylinder is soaking the rave valve with oil, this is only 4-6 hours of use after putting in new O-rings, bellows, and gaskets. The bellow is also slipping off where the larger spring ring is. I have one grooved and one not grooved. I forget which cylinder has which but I was also told they are just redesigned and should always be replaced with the grooved ones. Obviously one was replaced a while ago when it broke I am guessing.

What reason would there be so much oil on the valve and slightly spitting out between the two cylinders on the top end of the engine? Other then that ski runs good.

 

[scooper77515]

I don't know, but from my recent experience, mine was shooting oil past the RAVE and soon afterwards my engine failed on that cylinder.

Not sure if it was because of the RAVE (probably not) or the cylinder was failing and leaking past it.

Check which cylinder has which valve, swap the flat one to the front if possible, and see if it continues.

This is for my benefit, just to see if the groove RAVE caused, or had any help in failing my engine.

I doubt it will make a difference. I believe my cylinder had blow-by causing the RAVE to blow onto my engine...